arch/x86/entry/vdso/Makefile

   1 #
   2 # Building vDSO images for x86.
   3 #
   4
   5 KBUILD_CFLAGS += $(DISABLE_LTO)
   6 KASAN_SANITIZE                  := n
   7 UBSAN_SANITIZE                  := n
   8 OBJECT_FILES_NON_STANDARD       := y
   9
  10 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
  11 KCOV_INSTRUMENT         := n
  12
  13 VDSO64-$(CONFIG_X86_64)         := y
  14 VDSOX32-$(CONFIG_X86_X32_ABI)   := y
  15 VDSO32-$(CONFIG_X86_32)         := y
  16 VDSO32-$(CONFIG_IA32_EMULATION) := y
  17
  18 # files to link into the vdso
  19 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
  20
  21 # files to link into kernel
  22 obj-y                           += vma.o
  23 OBJECT_FILES_NON_STANDARD_vma.o := n
  24
  25 # vDSO images to build
  26 vdso_img-$(VDSO64-y)            += 64
  27 vdso_img-$(VDSOX32-y)           += x32
  28 vdso_img-$(VDSO32-y)            += 32
  29
  30 obj-$(VDSO32-y)                 += vdso32-setup.o
  31
  32 vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
  33
  34 $(obj)/vdso.o: $(obj)/vdso.so
  35
  36 targets += vdso.lds $(vobjs-y)
  37
  38 # Build the vDSO image C files and link them in.
  39 vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
  40 vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
  41 vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
  42 obj-y += $(vdso_img_objs)
  43 targets += $(vdso_img_cfiles)
  44 targets += $(vdso_img_sodbg)
  45 .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
  46         $(vdso_img-y:%=$(obj)/vdso%.so)
  47
  48 export CPPFLAGS_vdso.lds += -P -C
  49
  50 VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
  51                         -z max-page-size=4096
  52
  53 $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
  54         $(call if_changed,vdso)
  55
  56 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
  57 hostprogs-y                     += vdso2c
  58
  59 quiet_cmd_vdso2c = VDSO2C  $@
  60 define cmd_vdso2c
  61         $(obj)/vdso2c $< $(<:%.dbg=%) $@
  62 endef
  63
  64 $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
  65         $(call if_changed,vdso2c)
  66
  67 #
  68 # Don't omit frame pointers for ease of userspace debugging, but do
  69 # optimize sibling calls.
  70 #
  71 CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \
  72        $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
  73        -fno-omit-frame-pointer -foptimize-sibling-calls \
  74        -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
  75
  76 $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
  77
  78 #
  79 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
  80 #
  81 CFLAGS_REMOVE_vdso-note.o = -pg
  82 CFLAGS_REMOVE_vclock_gettime.o = -pg
  83 CFLAGS_REMOVE_vgetcpu.o = -pg
  84 CFLAGS_REMOVE_vvar.o = -pg
  85
  86 #
  87 # X32 processes use x32 vDSO to access 64bit kernel data.
  88 #
  89 # Build x32 vDSO image:
  90 # 1. Compile x32 vDSO as 64bit.
  91 # 2. Convert object files to x32.
  92 # 3. Build x32 VDSO image with x32 objects, which contains 64bit codes
  93 # so that it can reach 64bit address space with 64bit pointers.
  94 #
  95
  96 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
  97 VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
  98                            -z max-page-size=4096
  99
 100 # 64-bit objects to re-brand as x32
 101 vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
 102
 103 # x32-rebranded versions
 104 vobjx32s-y := $(vobjs64-for-x32:.o=-x32.o)
 105
 106 # same thing, but in the output directory
 107 vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
 108
 109 # Convert 64bit object file to x32 for x32 vDSO.
 110 quiet_cmd_x32 = X32     $@
 111       cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
 112
 113 $(obj)/%-x32.o: $(obj)/%.o FORCE
 114         $(call if_changed,x32)
 115
 116 targets += vdsox32.lds $(vobjx32s-y)
 117
 118 $(obj)/%.so: OBJCOPYFLAGS := -S
 119 $(obj)/%.so: $(obj)/%.so.dbg
 120         $(call if_changed,objcopy)
 121
 122 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
 123         $(call if_changed,vdso)
 124
 125 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
 126 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
 127
 128 # This makes sure the $(obj) subdirectory exists even though vdso32/
 129 # is not a kbuild sub-make subdirectory.
 130 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 131
 132 targets += vdso32/vdso32.lds
 133 targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
 134 targets += vdso32/vclock_gettime.o
 135
 136 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
 137 $(obj)/vdso32.so.dbg: KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
 138 $(obj)/vdso32.so.dbg: asflags-$(CONFIG_X86_64) += -m32
 139
 140 KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
 141 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
 142 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 143 KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
 144 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
 145 KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
 146 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 147 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 148 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
 149 KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING
 150 $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
 151
 152 $(obj)/vdso32.so.dbg: FORCE \
 153                       $(obj)/vdso32/vdso32.lds \
 154                       $(obj)/vdso32/vclock_gettime.o \
 155                       $(obj)/vdso32/note.o \
 156                       $(obj)/vdso32/system_call.o \
 157                       $(obj)/vdso32/sigreturn.o
 158         $(call if_changed,vdso)
 159
 160 #
 161 # The DSO images are built using a special linker script.
 162 #
 163 quiet_cmd_vdso = VDSO    $@
 164       cmd_vdso = $(LD) -nostdlib -o $@ \
 165                        $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
 166                        -T $(filter %.lds,$^) $(filter %.o,$^) && \
 167                  sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
 168
 169 VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
 170         $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
 171         -Bsymbolic
 172 GCOV_PROFILE := n
 173
 174 #
 175 # Install the unstripped copies of vdso*.so.  If our toolchain supports
 176 # build-id, install .build-id links as well.
 177 #
 178 quiet_cmd_vdso_install = INSTALL $(@:install_%=%)
 179 define cmd_vdso_install
 180         cp $< "$(MODLIB)/vdso/$(@:install_%=%)"; \
 181         if readelf -n $< |grep -q 'Build ID'; then \
 182           buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
 183           first=`echo $$buildid | cut -b-2`; \
 184           last=`echo $$buildid | cut -b3-`; \
 185           mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
 186           ln -sf "../../$(@:install_%=%)" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
 187         fi
 188 endef
 189
 190 vdso_img_insttargets := $(vdso_img_sodbg:%.dbg=install_%)
 191
 192 $(MODLIB)/vdso: FORCE
 193         @mkdir -p $(MODLIB)/vdso
 194
 195 $(vdso_img_insttargets): install_%: $(obj)/%.dbg $(MODLIB)/vdso
 196         $(call cmd,vdso_install)
 197
 198 PHONY += vdso_install $(vdso_img_insttargets)
 199 vdso_install: $(vdso_img_insttargets)
 200
 201 clean-files := vdso32.so vdso32.so.dbg vdso64* vdso-image-*.c vdsox32.so*